DE102020202317A1 - DEVICE FOR MEASURING PHOTOACOUSTIC WAVES - Google Patents

Abstract

A photoacoustic wave measurement device includes a laser beam output device and a measurement section. The laser beam output device outputs a laser beam. The measuring section measures an object to be measured based on a photoacoustic wave generated on the object to be measured by the laser beam. The laser beam output device has a pulsed laser output section that outputs a laser beam having a predetermined wavelength as first pulses; an optical path determining section that receives the first pulses and determines one of a plurality of optical paths for each pulse of the first pulses to be output; a wavelength changing section that receives light beams each passing through the plurality of optical paths and changes the light beams to have their respective different wavelengths for output; and a multiplexer that multiplexes the outputs from the wavelength changing section.

Description

BACKGROUND OF THE INVENTION

(FIELD OF THE INVENTION)

The present invention relates to measurement by means of a device that emits pulsed laser light of multiple wavelengths.

(DESCRIPTION OF THE RELATED ART STATEMENT)

Conventionally, the measurement (e.g. of the degree of oxygen saturation of the blood) as a reaction to (e.g. on the basis of the absorption coefficient of) pulsed light radiation from an object to be measured (e.g. a living organism) is known. It is also known that the response of an object to be measured varies depending on the wavelength of the pulsed light. Therefore, a desire has been expressed to irradiate an object to be measured with pulsed light of multiple wavelengths in order to increase the measurement accuracy. In this case, an increased time span between the irradiation of a point P of an object to be measured with pulsed light of one wavelength and the irradiation of point P with pulsed light of another wavelength can lead to a reduction in the measurement accuracy due to movement (e.g. body movement) of the object to be measured to lead.

However, no technique is known in which pulsed light of one wavelength is irradiated and immediately thereafter pulsed light of another wavelength is irradiated. For example, describe the Japanese Patent Laid-Open No. 2011-107094 , WO 2017/138619 , and the Japanese Patent Laid-Open No. 2016-101393 the multiplexing of laser beams with their respective different wavelengths, but not for the case of irradiation with pulsed light of one wavelength and immediately afterwards irradiation with pulsed light of another wavelength.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to carry out photoacoustic wave measurements by irradiating an object to be measured with pulsed light of one wavelength and immediately thereafter with pulsed light of another wavelength.

According to the present invention, an apparatus for measuring photoacoustic waves comprises: a laser beam output device that outputs a laser beam; and a measuring section that measures an object to be measured based on a photoacoustic wave generated on the object to be measured by the laser beam, wherein the laser beam output device comprises: a pulsed laser output section that receives a laser beam having a predetermined wavelength as outputs first pulse; an optical path determining section that receives the first pulses and determines one of a plurality of optical paths for each of the first pulses to be output; a wavelength changing section that receives light beams traveling through the plurality of optical paths, respectively, and changes the light beams to have their respective different wavelengths for output; and a multiplexer that multiplexes the outputs from the wavelength changing section.

According to the photoacoustic wave measuring device thus constructed, a laser beam output device outputs a laser beam. A measuring section measures an object to be measured based on a photoacoustic wave that the laser beam generates on the object to be measured. According to the laser beam output device, a pulsed laser output section outputs a laser beam having a predetermined wavelength as first pulses. An optical path determining section receives the first pulses and determines one of a plurality of optical paths for each of the first pulses to be output. A wavelength changing section receives light beams each passing through the plurality of optical paths, and changes the light beams so that they have their respective different wavelengths for output. A multiplexer multiplexes the output signals from the wavelength changing section.

According to the present invention, the photoacoustic wave measuring apparatus may further include an ultrasonic pulse output section that outputs an ultrasonic pulse, and the measuring section can further measure a reflected wave as a result of the reflection of the ultrasonic pulse on the object to be measured.

According to the photoacoustic wave measuring apparatus of the present invention, the first pulses may have a predetermined frequency, and the optical path determination section may output second pulses of a frequency obtained by dividing the predetermined frequency by the number of each of the plurality of optical paths which multiple optical paths are obtained and which each have different phases.

According to the photoacoustic wave measuring apparatus of the present invention, the multiplexer can output third pulses having the predetermined frequency.

According to the photoacoustic wave measuring apparatus of the present invention, the output portion of a pulsed laser may be a pump laser.

According to the photoacoustic wave measuring apparatus of the present invention, the optical path determining section may be an acousto-optic modulator or an acousto-optic deflector.

According to the photoacoustic wave measuring apparatus of the present invention, the wavelength changing portion may have polarization reversing portions disposed therebetween with a predetermined interval through which the light beams passing through propagate, and the predetermined distance may be different for each of the light beams passing through.

According to the photoacoustic wave measuring apparatus of the present invention, the wavelength changing portion may have a nonlinear optical crystal substrate with the polarization reversing portions formed therein, and the graphic centers of the polarization reversing portions may be arranged on a straight line parallel to an X-axis of the nonlinear optical crystal substrate.

According to the photoacoustic wave measuring apparatus of the present invention, the graphic centers of the polarization reversal cuts can be arranged on a straight line parallel to the traveling direction of the traveling light rays.

According to the photoacoustic wave measuring apparatus of the present invention, the wavelength changing section may comprise a nonlinear optical crystal substrate with all polarization reversing sections formed therein.

According to the photoacoustic wave measuring apparatus of the present invention, the wavelength changing portion may comprise a nonlinear optical crystal substrate with the polarization reversal portions formed therein, and the nonlinear optical crystal substrate may be provided for each of the light beams passing therethrough which propagate therethrough.

According to the photoacoustic wave measuring apparatus of the present invention, the wavelength changing section may comprise a nonlinear optical crystal through which the light rays passing therethrough propagate.

According to the present invention, the photoacoustic wave measuring apparatus may further include an optical fiber, one end of which receives an output from the multiplexer for output at the other end thereof.

According to the present invention, the device for measuring photoacoustic waves may further comprise a timing control section which times an output from the section for determining the optical path with an output of the first pulses.

According to the photoacoustic wave measuring apparatus of the present invention, the optical path determining section may include: a first acousto-optical modulator that receives the first pulses and determines one path among a plurality of optical paths for each of the first pulses to be output; and a second acousto-optic modulator that receives an output from the first acousto-optic modulator and determines a path of one or more optical paths for each pulse of the output from the first acousto-optic modulator for output.

According to the photoacoustic wave measuring apparatus of the present invention, the first acousto-optic modulator can bend or directly pass each of the first pulses to output, and the second acousto-optic modulator can receive and diffract the direct-pass pulses of the first pulses for output or directly pass through, while he receives the diffracted pulses of the first pulses for output and can pass them through directly.

According to the photoacoustic wave measuring apparatus of the present invention, the first acousto-optic modulator can bend or directly pass each pulse of the first pulses for output, and the second acousto-optic modulator can receive and diffract the diffracted pulses of the first pulses for output or directly pass through, while it receives the directly passed through pulses of the first pulses for output and can pass them through directly.

According to the photoacoustic wave measuring apparatus of the present invention, the first acousto-optic modulator can bend or directly pass each pulse of the first pulses to output, and the second acousto-optic modulator can bend each pulse of the output of the first acousto-optic modulator to output or pass through.

Figure list

• 1 Fig. 10 shows a configuration of a laser beam output device 1 according to a first embodiment;
• 2 Fig. 13 is a plan view of a wavelength changing section 14th according to the first embodiment;
• 3 shows timing diagrams of the first pulses P1 , the second pulse P2a (before the wavelength conversion), the second pulse P2b (after the wavelength conversion) and the third pulse P3b (after filtering) according to the first embodiment;
• 4th Fig. 13 is a plan view of a wavelength changing section 14th according to a variation of the first embodiment;
• 5 Fig. 10 shows a configuration of the laser beam output device 1 according to the second embodiment;
• 6th Fig. 10 shows a configuration of the laser beam output device 1 according to the third embodiment;
• 7th shows timing diagrams of the first pulses P1 , the second pulse P2a (before the wavelength conversion), the second pulse P2b (after the wavelength conversion) and the third pulse P3b (after filtering) according to the third embodiment;
• 8th Fig. 10 shows a configuration of the laser beam output device 1 according to the fourth embodiment;
• 9 Fig. 10 is an enlarged view around the optical path determination portion (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) in the laser beam output device 1 according to the fourth embodiment;
• 10 Fig. 10 shows a configuration of the laser beam output device 1 according to the fifth embodiment;
• 11 Fig. 13 is an enlarged view around the optical path determining portion (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) in the laser beam output device 1 according to the fifth embodiment;
• 12 Fig. 10 is an enlarged view around the optical path determination portion (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) in the laser beam output device 1 according to a variation of the fourth embodiment;
• 13 Fig. 13 is a functional block diagram showing a configuration of the photoacoustic wave measuring apparatus 100 according to the sixth embodiment of the present invention; and
• 14th Fig. 13 is a functional block diagram showing a configuration of the photoacoustic wave measuring apparatus 100 according to the seventh embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will now be given of embodiments of the present invention with reference to the drawings.

First embodiment

1 Fig. 10 shows a configuration of a laser beam output device 1 according to a first embodiment. 2 Fig. 13 is a plan view of a wavelength changing section 14th according to the first embodiment. 3 shows timing diagrams of the first pulses P1 , the second pulse P2a (before the wavelength conversion), the second pulse P2b (after the wavelength conversion) and the third pulse P3b (after filtering) according to the first embodiment. It is noted that in 3 the thickness and type (solid or broken) of the lines that indicate the pulses vary depending on the wavelength.

The laser beam output device 1 According to the first embodiment comprises a pump laser (output section of a pulsed laser) 10, an optical attenuator (ATT) 11 , an acousto-optic modulator (section for determining the optical path) (AOM) 12 , a wavelength changing section (PPLN) 14th , a mirror 15th , a dichroic mirror (multiplexer) (DCM) 16 , a filter (F) 17th , an optical fiber (MMF) 18th and a timing circuit (timing section) 19th .

The pump laser (output portion of a pulsed laser) 10 is arranged to emit a laser beam having a predetermined wavelength W1 [nm] as the first pulse P1 outputs at a predetermined frequency (e.g. 2 kHz) (see 3 ). The pump laser 10 is for example a Yb: YAG laser.

The optical attenuator (ATT) 11 is arranged so that it is the first pulse P1 attenuates and the acousto-optic modulator 12 feeds.

The acousto-optic modulator (section for determining the optical path) (AOM) 12 is arranged so that he gets the first pulse P1 receives and one of a plurality of optical paths OP1 , OP2 for each of the first pulses P1 intended for output.

For example, with reference to 1 and 3 , is at the time the acousto-optic modulator 12 odd-numbered (1st, 3rd, 5th ...) pulses of the first pulses P1 receives no acoustic wave to the acousto-optic modulator 12 provided. The odd-numbered pulses of the first pulses P1 then go directly through the acousto-optic modulator 12 (optical path OP1 ) through.

On the other hand, at the time the acousto-optic modulator 12 Even-numbered pulses (2nd, 4th, 6th ...) of the first pulses P1 receives an acoustic wave (with the angular frequency ω2) to the acousto-optic modulator 12 provided. The even-numbered pulses of the first pulses P1 then pass through the acousto-optic modulator 12 with some degree of diffraction (optical path OP2 ).

Note, however, that at the time the acousto-optic modulator 12 odd-numbered pulses of the first pulses P1 receives an acoustic wave (with an angular frequency ω1 different from ω2) to the acousto-optic modulator 12 can be provided.

This causes the acousto-optic modulator 12 on the multiple optical paths OP1 , OP2 second pulse each time P2a (before wavelength conversion) at a frequency (1 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (two) of the plural optical paths and each having a phase different by 180 degrees.

The timing circuit (section on timing) 19th is arranged so that an output of the acousto-optical modulator (section for determining the optical path) 12 is based on an output of the first pulses P1 is timed. The result of timing control has so far been referring to 3 described. It should be noted that the timing control circuit 19th is arranged to provide a signal in synchronism with the timing of the output of the first pulse P1 from the pump laser (output section of a pulsed laser) 10 and, based on this signal, the timing of the output from the acousto-optic modulator 12 controls.

The Wavelength Changing Section (PPLN) 14th is arranged to emit light rays (i.e. second pulses P2a ) each through the multiple optical paths OP1 , OP2 move through it, and change the light rays so that they have their respective different wavelengths for output. The wavelength changing section 14th gives second pulses P2b (after the wavelength conversion).

In relation to 3 is the wavelength changing section 14th arranged so that it generates pulses (wavelength W1 [nm]) of the second pulse P2a showing the optical path OP1 pass through, receive and in second pulses P2b (Wavelength W2 [nm]). The wavelength changing section 14th is also arranged to generate pulses (wavelength W1 [nm]) of the second pulse P2a showing the optical path OP2 pass through, receive and in second pulses P2b (Wavelength W3 [nm]).

In relation to 2 has the wavelength changing section 14th an LN crystal substrate 142 and polarization reversal sections 144 . It is noted that in 2 , in contrast to 1 , the X-axis direction of the LN crystal substrate 142 is shown for illustration parallel to the longitudinal direction of the drawing sheet.

The polarization reversal sections 144 are arranged so that light rays passing through (i.e. second pulses P2a ) through them. The polarization reversal sections 114 have those through which the second pulses P2a showing the optical path OP1 traverse, spread, and others through which the second pulses P2a showing the optical path OP2 go through, spread out. It is noted that the polarization reversing sections 144 in 2 consist of PPLN (periodically polarization reversed lithium niobate), but are not limited to it and can consist of, for example, PPLT (lithium tantalate) or PPKTP.

The polarization reversal sections 144 through which the second pulses P2a showing the optical path OP1 run through are at a predetermined distance D1 arranged. The polarization reversal sections 144 through which the second pulses P2a showing the optical path OP2 traverse, spread, are at a predetermined distance D2 arranged. The predetermined distance varies from one light beam passing through to another. That is, the predetermined distance D1 differs from the predetermined distance D2 .

The polarization reversal sections 144 are in the LN crystal substrate 142 educated. All polarization reversal sections 144 are in the LN crystal substrate 142 educated. It should be noted that the LN crystal substrate 142 in the first embodiment may not be an LN crystal substrate as long as it is a nonlinear optical crystal substrate. This applies to other embodiments in which a nonlinear optical crystal substrate can be used in place of such an LN crystal substrate.

The graphic centers 144c the polarization reversal sections 144 , through which the second pulses P2a showing the optical path OP1 traversed, spread, are on a straight line parallel to the X-axis of the LN crystal substrate 142 arranged. The graphic centers 144c the polarization reversal sections 144 , through which the second pulses P2a showing the optical path OP2 traversing, spreading, are also on a straight line parallel to the X-axis of the LN crystal substrate 142 arranged. It should be noted that the graphic centers 144c the polarization reversal sections 144 correspond to the centers of gravity, assuming that the force of gravity acts equally on each polarization reversal section 144 works.

The mirror 15th is arranged so that it pulses the second pulse P2b (after wavelength conversion) that receives the optical path OP2 go through and take them to the dichroic mirror 16 reflected.

The dichroic mirror (multiplexer) (DCM) 16 is arranged to be from the wavelength changing section 14th Pulse of the second pulse P2b (after the wavelength conversion) received from the wavelength changing section 14th output and the optical path OP1 run through. The dichroic mirror 16 is also arranged so that it is from the mirror 15th Pulse of the second pulse P2b (after the wavelength conversion) received from the wavelength changing section 14th output and the optical path OP2 run through. The dichroic mirror 16 is also arranged to receive pulses of the second pulse P2b (after the wavelength conversion) taken from the wavelength changing section 14th and the optical paths OP1 and OP2 run through, multiplexed and third pulses P3a (before filtering) at a predetermined frequency (2 kHz).

Note, however, that in addition to the third pulses P3a (before filtering) a laser beam (pump beam) emitted by the pump laser 10 is output and a wavelength W1 [nm], and an infrared idle beam emerging from the wavelength changing section 14th originates, also in the dichroic mirror output 16 be mixed. It should be noted that the wavelength changing section 14th When a laser beam (pump beam) is applied to it, a signal beam and such an idle beam, as described above, are generated due to the optical parametric oscillation. That is, the signal beam becomes the wavelength changing section 14th (as a second pulse P2b (after the wavelength conversion)) (the same applies to wavelength changing sections according to other embodiments).

The filter (F) 17th is arranged to have the pump beam and the idle beam from the third pulses P3a (before filtering) removed to third pulse P3b (after filtering).

The optical fiber (MMF) 18th is arranged so that it receives the third pulse at one end P3a receives that from the dichroic mirror 16 through the filter 17th for output at the other end.

Next, an operation according to the first embodiment will be described.

The pump laser 10 first emits a laser beam with a predetermined wavelength W1 [nm] as the first pulse P1 with a predetermined frequency (e.g. 2 kHz) (see 3 ). The first pulses P1 are through the optical damper 11 attenuated and the acousto-optic modulator 12 fed. The timing circuit 19th controls the timing of the output of the acousto-optic modulator 12 (please refer 3 ).

At the time the acousto-optic modulator 12 odd-numbered (1st, 3rd, 5th ...) pulses of the first pulses P1 receives no acoustic wave to the acousto-optic modulator 12 provided. This results in the odd numbered pulses being the first pulse P1 directly through the acousto-optic modulator 12 (optical path OP1 ) go. This causes the rays of light that make up the optical path OP1 run through, second pulses P2a (before wavelength conversion) having a frequency (1 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (two) of the multiple optical paths.

At the time the acousto-optic modulator 12 Even-numbered (2nd, 4th, 6th ...) pulses of the first pulses P1 receives an acoustic wave (with the angular frequency ω2) to the acousto-optic modulator 12 provided. This causes the even-numbered pulses to be the first pulses P1 the acousto-optic modulator 12 traverse with a certain degree of diffraction (optical path OP2 ). This causes rays of light to enter the optical path OP2 run through, second pulses P2a (before wavelength conversion) having a frequency (1 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (two) of the multiple optical paths.

In addition, the phase of the light rays that follow the optical path is different OP1 (second pulse P2a (before the wavelength conversion)) traversed 180 degrees from the phase of the light rays making the optical path OP2 (second pulse P2a (before the wavelength conversion)).

The ones through the optical path OP1 (second pulse P2a (before wavelength conversion), with a wavelength W1 [nm]) passing light rays propagate through the polarization reversal sections 144 from that at the predetermined distance D1 in the wavelength changing section 14th are arranged to undergo wavelength conversion in W2 [nm] and the dichroic mirror 16 as a second pulse P2b (after wavelength conversion) to be provided.

The ones through the optical path OP2 (second pulse P2a (before wavelength conversion), with a wavelength W1 [nm]) traveling light rays propagate through the polarization reversal sections 144 from that at the predetermined distance D2 in the wavelength changing section 14th are arranged to undergo wavelength conversion to W3 [nm] and are made by the mirror 15th reflected and the dichroic mirror 16 as a second pulse P2b (after wavelength conversion) provided.

Individual of the second pulses P2b (after the wavelength conversion) by the wavelength changing section 14th output and which is the wavelength W2 [nm] and the wavelength W3 [nm] are reflected by the dichroic mirror 16 as a third pulse P3a (before filtering) multiplexed at a predetermined frequency (2 kHz).

The third pulse P3a (before filtering) are through the filter 17th away from the pump beam and the idle beam and become third pulses P3b (after filtering). The third pulse P3b (after filtering) will be at one end of the optical fiber 18th ready for output at the other end.

According to the first embodiment, the third pulses P3b (after filtering) from the optical fiber 18th are issued. The third pulse P3b (after filtering) ensure irradiation with pulsed light of wavelength W2 [nm] and immediately afterwards (eg after 500 microseconds) for irradiation with pulsed light of different wavelengths W3 [nm]. That is, the first embodiment allows the irradiation with pulsed light of one wavelength and immediately thereafter (for example after 500 microseconds) the irradiation with pulsed light of another wavelength.

It is noted that the graphic centers 144c the polarization reversal cuts 144 in the first embodiment (see 2 ) on a straight line parallel to the X-axis of the LN crystal substrate 142 are arranged, but they can also be arranged as in the following variant.

4th Fig. 13 is a plan view of a wavelength changing section 14th according to a variation of the first embodiment. It is noted that in 4th , different from in 1 , but as in 2 , the X-axis direction of the LN crystal substrate 142 is shown for illustration parallel to the longitudinal direction of the drawing sheet.

In relation to 4th are in the wavelength changing section 14th according to the variation of the first embodiment, the polarization reversal sections 144 through which the light rays passing through (second pulses P2a showing the optical path OP1 run through), at a predetermined distance D1 arranged and their graphic centers 144c on a straight line parallel to the direction of propagation (eg on the direction of propagation) of the light rays passing through (second pulses P2a showing the optical path OP1 run through). The polarization reversal sections 144 through which the light rays passing through (second pulses P2a showing the optical path OP2 run through) are also at a predetermined distance D2 arranged, and their graphic centers 144c are on a straight line parallel to the direction of propagation (eg on the direction of propagation) of the light rays passing through (second pulses P2a showing the optical path OP2 run through).

In accordance with the above-described variation of the first embodiment, the longitudinal length of each polarization reversing portion can be 144 (in the direction of the Y-axis) can be reduced compared to the longitudinal length of the first embodiment.

While the polarization reversal sections 144 in the first embodiment in the wavelength changing section 14th are provided (see and ), another variant can have a non-linear optical crystal through which the light rays pass without these polarization reversal sections 144 spread. For example, the wavelength changing section 14th BPM (birefringent phase adjustment) based on OPO (optical parametric oscillation), SHG (generation of a second harmonic), THG (generation of a third harmonic) or the like.

Second embodiment

A laser beam output device 1 According to a second embodiment, it is arranged such that LN crystal substrates are provided for the respective light beams passing therethrough which propagate therethrough coming from the laser beam output device 1 according to the first embodiment, in which the single LN crystal substrate 142 is provided.

5 Fig. 10 shows a configuration of the laser beam output device 1 according to the second embodiment. The laser beam output device 1 According to the second embodiment comprises a pump laser (output section of a pulsed laser) 10, an optical attenuator (ATT) 11 , an acousto-optic modulator (section for determining the optical path) (AOM) 12 , a rhomboid prism 13 , Wavelength change ranges (PPLN) 14a , 14b , a mirror 15th , a dichroic mirror (multiplexer) (DCM) 16 , a filter (F) 17th , an optical fiber (MMF) 18th and a timing circuit (timing section) 19th . Components that are identical to those of the first embodiment are given the same reference numerals in the following to omit the description of these components.

The pump laser (output section of a pulsed laser) 10, the optical attenuator (ATT) 11 , the acousto-optic modulator (section for determining the optical path) (AOM) 12 , the mirror 15th , the dichroic mirror (multiplexer) (DCM) 16 , the filter (F) 17th , the optical fiber (MMF) 18th and the timing circuit (timing section) 19th are identical to those of the first embodiment, and the description thereof has been omitted.

The rhomboid prism 13 is arranged so that it pulses the second pulse P2a (before wavelength conversion) that receives the optical path OP2 and the optical path parallel to the optical path OP1 changed away.

The Wavelength Changing Section (PPLN) 14a is arranged so that it is from the acousto-optic modulator 12 Pulse of the second pulse P2a (Wavelength W1 [nm]) representing the optical path OP1 pass through, receive and in second pulses P2b (Wavelength W2 [nm]). The arrangement of the wavelength changing section 14a corresponds to the predetermined distance D1 arranged polarization reversal sections 144 and the LN crystal substrate 142 in which the polarization reversal sections 144 be formed as in 2 or 4th shown.

The Wavelength Changing Section (PPLN) 14b is arranged so that it diverges from the rhomboid prism 13 Pulse of the second pulse P2a (Wavelength W1 [nm]) representing the optical path OP2 pass through, receive and in second pulses P2b (Wavelength W3 [nm]). The arrangement of the wavelength changing section 14b corresponds to the predetermined distance D2 arranged polarization reversal sections 144 and the LN crystal substrate 142 in which the polarization reversal sections 144 be formed as in 2 or 4th shown.

It should be noted that the LN crystal substrate that is the wavelength changing portion 14a is not identical to the LN crystal substrate that the wavelength changing section 14b having. That is, the LN crystal substrate that has the wavelength changing section 14a and the LN crystal substrate having the wavelength changing portion 14b each for the light rays (which make up the optical path OP1 and the optical path OP2 run through), which spread through them.

Since the operation of the second embodiment is identical to that of the first embodiment, the description of the second embodiment is omitted.

According to the second embodiment, the LN crystal substrates are respectively for the light beams (which form the optical path OP1 and the optical path OP2 run through) provided, the manufacturing conditions for the polarization reversal sections 144 according to the predetermined distance D1 , D2 can be adjusted what the manufacture of the wavelength changing sections 14a , 14b facilitated.

Third embodiment

The laser beam output device 1 according to the third embodiment is different from the laser beam output device 1 according to the first embodiment in that instead of the acousto-optical modulator (AOM) (section for determining the optical path) 120 . an acousto-optic deflector (AOD) is used (section for determining the optical path) 12.

6th Fig. 10 shows a configuration of the laser beam output device 1 according to the third embodiment. 7th shows timing diagrams of the first pulses P1 , the second pulse P2a (before the wavelength conversion), the second pulse P2b (after the wavelength conversion) and the third pulse P3b (after filtering) according to the third embodiment. It should be noted that in 7th the thickness and type (continuous, interrupted or alternating long and short dashes) of the lines that indicate the pulses vary depending on the wavelength.

The laser beam output device 1 According to the third embodiment comprises a pump laser (output section of a pulsed laser) 10, an optical attenuator (ATT) 11 , an acousto-optic deflector (AOD) (section for determining the optical path) 120 , a wavelength changing section (PPLN) 14th , a mirror 154 , a dichroic mirror (multiplexer) (DCM) 162 , 164 , a filter (F) 17th , an optical fiber (MMF) 18th and a timing circuit (timing section) 19th . Components that are identical to those of the first embodiment are given the same reference numerals in the following to omit the description of these components.

The pump laser (output section of a pulsed laser) 10, the optical attenuator (ATT) 11 , the filter (F) 17th , the optical fiber (MMF) 18th and the timing circuit (timing section) 19th are identical to those of the first embodiment, and the description thereof is omitted. Note, however, that the timing circuit 19th the timing of the output of the acousto-optic deflector 120 . controls (see 7th ).

The acousto-optic deflector (AOD) (section for determining the optical path) 120 . is arranged so that he gets the first pulse P1 receives and one of several optical paths OP1 , OP2 , OP3 for each pulse of the first pulse P1 intended for output.

For example, with reference to 6th and 7th , will at the time when the acousto-optic deflector 120 . (1 + 3N) -numbered (1st, 4th, 7th ...) pulses (where N is an integer equal to or greater than 0) of the first pulses P1 receives no acoustic wave to the acousto-optic deflector 120 . provided. The (1 + 3N) -numbered pulses of the first pulses P1 then go straight through the acousto-optic deflector 120 . through (optical path OP1 ).

On the other hand, at the time the acousto-optic deflector 120 . (2 + 3N) -numbered (2nd, 5th, 8th ...) pulses of the first pulses P1 receives an acoustic wave (with angular frequency ω2) to the acousto-optic deflector 120 . provided. The (2 + 3N) -numbered pulses of the first pulses P1 then pass through the acousto-optic deflector 120 . with a certain degree of diffraction (optical path OP2 ).

At the time the acousto-optic deflector 120 . (3 + 3N) -numbered (3rd, 6th, 9th ...) coil of the first pulse P1 receives, becomes the acousto-optic deflector 120 . an acoustic wave (with an angular frequency ω3 different from ω2) is also supplied. The (3 + 3N) -numbered pulses of the first pulses P1 then pass through the acousto-optic deflector 120 . with some degree of diffraction (optical path OP3 ). Note, however, that the angle between the optical path OP3 and the optical path OP1 (less than 90 degrees) is greater than the angle between the optical path OP2 and the optical path OP1 (less than 90 degrees).

It should be noted that at the time the acousto-optic deflector 120 . (1 + 3N) -numbered pulses of the first pulses P1 receives an acoustic wave (with an angular frequency ω1 which differs from ω2 and ω3) to the acousto-optic deflector 120 . can be provided.

This leads to the acousto-optic deflector 120 . on the multiple optical paths OP1 , OP2 , OP3 second pulse each time P2a (before wavelength conversion) which have a frequency (2/3 kHz) obtained by dividing the predetermined frequency (e.g., 2 kHz) by the number (three) of the plural optical paths and each of 120 . Degrees have different phases.

The Wavelength Changing Section (PPLN) 14th is arranged to emit light rays (i.e. second pulses P2a ), each through the different optical paths OP1 , OP2 , OP3 pass through, and change the light rays so that they have their respective different wavelengths for output. The wavelength changing section 14th gives second pulses P2b (after the wavelength conversion).

With reference to 7th is the wavelength changing section 14th arranged so that it pulses the second pulse P2a (Wavelength W1 [nm]) representing the optical path OP1 pass through, receive and in second pulses P2b (Wavelength W2 [nm]). The wavelength changing section 14th is also arranged to generate pulses (wavelength W1 [nm]) of the second pulse P2a showing the optical path OP2 pass through, receive and in second pulses P2b (Wavelength W3 [nm]). The wavelength changing section 14th is also arranged to generate pulses (wavelength W1 [nm]) of the second pulse P2a going through the optical path OP3 run, receive and in second pulses P2b (Wavelength W4 [nm]).

The wavelength changing section 14th has a configuration similar to that of the first embodiment and its variation (see and ). Note, however, that the polarization reversal sections 144 through which the second pulses P2a going through the optical path OP3 run through, spread out, at a predetermined distance D3 are arranged (where D3 differs from D1 and D2).

The mirror 154 is arranged so that it pulses the second pulse P2b (after wavelength conversion) that receives the optical path OP3 traverse them and point them towards the dichroic mirror 162 reflected.

The dichroic mirror (multiplexer) (DCM) 162 is arranged so that it pulses the second pulse P2b (after the wavelength conversion) that the optical path OP2 go through, and the one from the mirror 154 reflected light rays (pulses second pulses P2b (after the wavelength conversion)) which the optical path OP3 traversed, multiplexed and towards the dichroic mirror 164 reflected.

The dichroic mirror (multiplexer) (DCM) 164 is arranged so that it pulses the second pulse P2b (after the wavelength conversion) that the optical path OP1 pass through, and the light rays from the dichroic mirror 162 (Multiplexing pulses from the second pulse P2b (after the wavelength conversion)) which the optical path OP2 and the optical path OP3 run through, multiplexed and third pulses P3a (before filtering) at a predetermined frequency of 2 kHz.)

Next, an operation according to the third embodiment will be described.

The pump laser 10 first emits a laser beam with a predetermined wavelength W1 [nm] as the first pulse P1 with a predetermined frequency (e.g. 2 kHz) (see 7th ). The first pulses P1 are through the optical damper 11 muffled and the acousto-optic deflector 120 . fed. The timing circuit 19th controls the timing of the output of the acousto-optic deflector 120 . (please refer 7th ).

At the time the acousto-optic deflector 120 . (1 + 3N) -numbered (1st, 4th, 7th ...) pulses of the first pulses P1 receives no acoustic wave at the acousto-optic deflector 120 . provided. The (1 + 3N) -numbered pulses of the first pulses P1 then go straight through the acousto-optic deflector 120 . through (optical path OP1 ). This causes rays of light to enter the optical path OP1 run through, second pulses P2a (before the wavelength conversion) having a frequency (2/3 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (three) of the multiple optical paths.

At the time the acousto-optic deflector 120 . (2 + 3N) -numbered (2nd, 5th, 8 ...) pulses of the first pulses P1 receives an acoustic wave (with the angular frequency ω2) to the acousto-optic deflector 120 . provided. The (2 + 3N) -numbered pulses of the first pulses P1 then pass through the acousto-optic deflector 120 . with a certain degree of diffraction (optical path OP2 ). This causes the light rays that make up the optical path OP2 run through to second pulses P2a (before the wavelength conversion) at a frequency (2/3 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (three) of multiple optical paths.

At the time the acousto-optic deflector 120 . (3 + 3N) -numbered (3rd, 6th, 9th ...) pulses of the first pulses P1 receives an acoustic wave (with an angular frequency ω3) to the acousto-optic deflector 120 . provided. The (3 + 3N) -numbered pulses of the first pulses P1 then pass through the acousto-optic deflector 120 . with a certain degree of diffraction (optical path OP3 ). This causes the light rays that make up the optical path OP3 run through to second pulses P2a (before the wavelength conversion) at a frequency (2/3 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (three) of multiple optical paths.

In addition, the phase of the light rays that follow the optical path is different OP1 (second pulse P2a (before wavelength conversion)) run through to 120 . Degree of the phase of the light rays that make up the optical path OP2 (second pulse P2a (before the wavelength conversion)). The phase of the light rays passing through the optical path OP2 (second pulse P2a (before the wavelength conversion)) is different by 120 . Degree of the phase of the light rays passing through the optical path OP3 (second pulse P2a (before the wavelength conversion)) pass through. The phase of the light rays passing through the optical path OP1 (second pulse P2a (before wavelength conversion)) is 240 degrees different from the phase of light rays passing through the optical path OP3 (second pulse P2a (before the wavelength conversion)) pass through.

The ones through the optical path OP1 (second pulse P2a (before wavelength conversion), with a wavelength W1 [nm]) passing light rays propagate through the polarization reversal sections 144 from that at the predetermined distance D1 in the wavelength changing section 14th are arranged to undergo wavelength conversion in W2 [nm] and the dichroic mirror 164 as a second pulse P2b (after the wavelength conversion) to be supplied.

The the optical path OP2 (second pulse P2a (before wavelength conversion), with a wavelength W1 [nm]) passing light rays propagate through the polarization reversal sections 144 from that at the predetermined distance D2 in the wavelength changing section 14th are arranged to undergo wavelength conversion into W3 [nm] and are made by the dichroic mirror 162 reflected and the dichroic mirror 164 as a second pulse P2b (after the wavelength conversion) supplied.

The ones through the optical path OP3 (second pulse P2a (before wavelength conversion), with a wavelength W1 [nm]) passing light rays propagate through the polarization reversal sections 144 from that at the predetermined distance D3 in the wavelength changing section 14th are arranged to undergo wavelength conversion in W4 [nm] and are made by the mirror 154 reflected and through the dichroic mirror 162 as a second pulse P2b (after the wavelength conversion) the dichroic mirror 164 fed.

Pulse of the second pulse P2b (after the wavelength conversion) by the wavelength changing section 14th output and which is the wavelength W2 [nm], the wavelength W3 [nm] and the wavelength W4 [nm] are reflected by the dichroic mirror 164 to third pulses P3a (before filtering) multiplexed at a predetermined frequency (2 kHz).

The third pulse P3a (before filtering) experience removal of the pump beam and the idle beam through the filter 17th at third pulses P3b (after filtering) to become. The third pulse P3b (after filtering) will be at one end of the optical fiber 18th ready for output at the other end.

According to the third embodiment, instead of the acousto-optic modulator 12 the acousto-optic deflector 120 . is used, the number of the plurality of optical paths can be increased to three (optical paths OP1 , OP2 , OP3 ). The third pulse P3b (after filtering) thus ensure the irradiation with pulsed light of the wavelength W2 [nm] and immediately afterwards (eg after 500 microseconds) for irradiation with pulsed light of different wavelengths W3 [nm]. It also sees the irradiation with pulsed light of the wavelength W3 [nm] and immediately afterwards (eg after 500 microseconds) irradiation with pulsed light of other different wavelengths W4 [nm] before. That is, the third embodiment allows the irradiation with pulsed light of one wavelength, immediately thereafter the irradiation with pulsed light of another wavelength and immediately thereafter the irradiation with pulsed light of a further wavelength. The third embodiment thus allows irradiation with pulsed light of three wavelengths.

It should be noted that the number of the multiple optical paths may be four or more, although in the third embodiment described above, the number is three. This enables the irradiation with pulsed light of four or more wavelengths.

In the third embodiment, too, as in the first, there is only one LN crystal substrate 142 . All polarization reversal sections 144 are in the single LN crystal substrate 142 educated. However, LN crystal substrates can be used for the light rays (which make up the optical path OP1 , the optical path OP2 and the optical path OP3 pass), which spread there, are provided, as is the case with the second embodiment.

Fourth embodiment

The laser beam output device 1 according to the fourth embodiment is different from the laser beam output device 1 according to the third embodiment mainly in that instead of the acousto-optic deflector (AOD) (section for determining the optical path) 120 . a section for determining the optical path (a first acousto-optic modulator (AOM) 12a and a second acousto-optic modulator (AOM) 12b) is used.

8th Fig. 10 shows a configuration of the laser beam output device 1 according to the fourth embodiment. 9 Fig. 10 is an enlarged view around the optical path determination portion (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) in the laser beam output device 1 according to the fourth embodiment around.

The laser beam output device 1 According to the fourth embodiment, comprises a pump laser (output section of a pulsed laser) 10 , optical attenuators (ATT) 11a , 11b , 11c , a first acousto-optic modulator (AOM) 12a , a second acousto-optic modulator (AOM) 12b , rhomboid prisms 13a , 13b , Wavelength change sections (PPLN) 14a , 14b , 14c , a mirror 154 , dichroic mirrors (multiplexer) (DCM) 162 , 164 , Filter (F) 172 , 174 , 176 , an optical fiber (MMF) 18th , a timing circuit (section on timing) 19th and a lens (L) 192 . Components that are identical to those of the third embodiment are given the same reference numerals below to omit the description of these components.

The pump laser (output section of a pulsed laser) 10, the mirror 154 , Dichroic Mirrors (Multiplexers) (DCM) 162,164, Optical Fiber (MMF) 18th and the timing circuit (timing section) 19th are identical to those in the third embodiment, and the description thereof is omitted. Note, however, that the optical fiber (MMF) 18th is arranged so that it has the third pulse at one end P3 receives that from the dichroic mirror 164 over the lens (L) 192 for output on the other Be issued at the end. It should also be noted that the timing control circuit 19th is arranged so that it is the timing of the output of the section for determining the optical path (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) controls (see P2a in 7th ).

The section for determining the optical path has the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b on. Both the first acousto-optic modulator (AOM) 12a as well as the second acousto-optic modulator (AOM) 12b have a rectangular, planar shape.

One of the longer sides of the first acousto-optic modulator (AOM) 12a receives the first pulses P1 . The shorter sides of the first acousto-optic modulator (AOM) 12a are opposite the optical path OP2 inclined by θB (Bragg angle) counterclockwise.

One of the longer sides of the second acousto-optic modulator (AOM) 12b receives the output signal of the first acousto-optic modulator (AOM) 12a . The shorter sides of the second acousto-optic modulator (AOM) 12b are opposite the optical path OP2 inclined clockwise by θB (Bragg angle).

The first acousto-optic modulator (AOM) 12a is arranged so that he gets the first pulse P1 receives and one path of multiple optical paths OP1 , OP2 for each pulse of the first pulse P1 intended for output. In the fourth embodiment, the first acousto-optic modulator (AOM) 12a arranged so that it gets every pulse of the first pulse P1 bends to output (optical path OP1 ) or forwards directly (optical path OP2 ).

The second acousto-optic modulator (AOM) 12b is arranged to receive the output of the first acousto-optic modulator 12a receives and one path from one or more optical paths OP1 , OP2 , OP3 for each pulse of the pulses of the output of the first acousto-optic modulator 12a intended for output. In the fourth embodiment, the second acousto-optic modulator (AOM) 12b arranged in such a way that the directly transmitted pulses of the first pulses (optical path OP2 ) for output receives and diffracts (optical path OP3 ) or forwards directly (optical path OP2 ), while he sees the diffracted pulses (optical path OP1 ) receives the first pulse for output and forwards it directly (optical path OP1 ).

It should be noted that the timing diagrams of the first pulses P1 , the second pulse P2a (before the wavelength conversion), the second pulse P2b (after the wavelength conversion) and the third pulse P3 (Entrance into the optical fiber (MMF) 18th ) according to the fourth embodiment identical to those in 7th are (where P3b in 7th should be read as P3).

For example, regarding 9 and 7th at the point in time at which the section for determining the optical path (1 + 3N) -numbered (1st, 4th, 7th ...) pulses (where N is an integer equal to or greater than 0) of the first pulses P1 receives an acoustic wave to the first acousto-optic modulator (AOM) 12a provided during the second acousto-optic modulator (AOM) 12b no acoustic wave is provided. The (1 + 3N) -numbered pulses of the first pulses P1 then traverse the optical path OP1 (please refer 9 ).

At the point in time at which the section for determining the optical path (2 + 3N) -numbered (2nd, 5th, 8th ...) pulses of the first pulses P1 receives the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b no acoustic wave supplied. The (2 + 3N) -numbered pulses of the first pulses P1 then traverse the optical path OP2 (please refer 9 ).

At the point in time at which the section for determining the optical path (3 + 3N) -numbered (3rd, 6th, 9th ...) pulses of the first pulses P1 receives the first acousto-optic modulator (AOM) 12a no acoustic wave fed during the second acousto-optic modulator (AOM) 12b an acoustic wave is supplied. The (3 + 3N) -numbered pulses of the first pulses P1 then traverse the optical path OP3 (please refer 9 ).

As a result, the section for determining the optical path is on the multiple optical paths OP1 , OP2 , OP3 second pulse each time P2a (before wavelength conversion) which have a frequency (2/3 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (three) of the plural optical paths and which are each by 120 . Degrees have different phases.

The rhomboid prism 13a is arranged so that it pulses the second pulse P2a (before wavelength conversion) that receives the optical path OP1 and the optical path parallel to the optical path OP1 changed away. The rhomboid prism 13b is arranged so that it pulses the second pulse P2a (before wavelength conversion) received by the optical path OP3 pass through, and the optical path parallel to the optical path OP3 way changes.

The optical attenuators (ATT) 11a , 11b , 11c are arranged so that they block the light rays passing through the optical path OP1 (Edition of the rhomboid prism 13a ), the rays of light passing through the optical path OP2 and the light rays passing through the optical path OP3 (Edition of the rhomboid prism 13b ) run, weaken them and match them to the wavelength change sections (PPLN) 14a , 14b , 14c respectively.

Since the wavelength changing sections (PPLN) 14a , 14b are identical to those of the second embodiment, their description is omitted. The Wavelength Changing Section (PPLN) 14c is arranged so that it diverges from the rhomboid prism 13b Pulse receives and Pulse (wavelength W1 [nm]) of the second pulse P2a showing the optical path OP3 run through, in second pulses P2b (Wavelength W4 [nm]). The arrangement of the wavelength changing section 14b corresponds to the predetermined distance D2 arranged polarization reversal sections 144 (where the predetermined distance D2 should be read as D3) and the LN crystal substrate 142 in which the polarization reversal sections 144 be formed as in 2 or 4th shown.

It should be mentioned that the LN crystal substrate that is the wavelength changing section 14a the LN crystal substrate which is the wavelength changing portion 14b and the LN crystal substrate that is the wavelength changing portion 14c are not identical. That is, the LN crystal substrate that is the wavelength changing portion 14a the LN crystal substrate which is the wavelength changing portion 14b and the LN crystal substrate that is the wavelength changing portion 14c are each for the light rays (which travel through the optical path OP1 , the optical path OP2 and the optical path OP3 spread) provided.

The filters (F) 172 , 174 , 176 are arranged in such a way that they take the pump beam and the idle beam from the outputs of the wavelength changing sections (PPLN) 14a , 14b , 14c for output to the dichroic mirror (multiplexer) (DCM) 164 , 162 and the mirror 154 remove.

The lens (L) 192 is arranged in such a way that it receives the output signal of the dichroic mirror (multiplexer) (DCM) 164 receives and to the optical fiber (MMF) 18th forwards.

Next, an operation according to the fourth embodiment will be described.

The pump laser 10 first emits a laser beam with a predetermined wavelength W1 [nm] as the first pulse P1 with a predetermined frequency (e.g. 2 kHz) (see 7th ). The first pulses P1 become the first acousto-optic modulator (AOM) 12a of the section for determining the optical path supplied. The timing circuit 19th controls the timing of the output of the section for determining the optical path (see P2a in 7th ).

At the point in time at which the section for determining the optical path (1 + 3N) -numbered (1st, 4th, 7th ...) pulses (where N represents an integer equal to or greater than 0) of the first pulses P1 receives, an acoustic wave is sent to the first acousto-optic modulator (AOM) 12a while the second acousto-optic modulator (AOM) 12b no acoustic wave is supplied. The (1 + 3N) -numbered pulses of the first pulses P1 then traverse the optical path OP1 (please refer 9 ). This causes the light rays that make up the optical path OP1 run through to second pulses P2a (before wavelength conversion) at a frequency (2/3 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (three) of multiple optical paths (see 7th ).

At the point in time at which the section for determining the optical path (2 + 3N) -numbered (2nd, 5th, 8th ...) pulses of the first pulses P1 receives the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b no acoustic wave supplied. The (2 + 3N) -numbered pulses of the first pulses P1 then traverse the optical path OP2 (please refer 9 ). This causes the light rays that make up the optical path OP2 run through to second pulses P2a (before the wavelength conversion) at a frequency (2/3 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (three) of multiple optical paths (see 7th ).

At the point in time at which the section for determining the optical path (3 + 3N) -numbered (3rd, 6th, 9th ....) pulses of the first pulses P1 receives the first acousto-optic modulator (AOM) 12a no acoustic wave fed during the second acousto-optic modulator (AOM) 12b an acoustic wave is supplied. The (3 + 3N) -numbered pulses of the first pulses P1 then traverse the optical path OP3 (please refer 9 ). This causes the light rays that make up the optical path OP3 run through to second pulses P2a (before wavelength conversion) at a frequency (2/3 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (three) of multiple optical paths (see 7th ).

In addition, the phase of the light rays that follow the optical path is different OP1 (second pulse P2a (before the wavelength conversion)) traversed 120 degrees from the phase of the light rays making the optical path OP2 (second pulse P2a (before the wavelength conversion)). The phase of the light rays passing through the optical path OP2 (second pulse P2a (before wavelength conversion)) differs by 120 degrees from the phase of the light rays passing through the optical path OP3 (second pulse P2a (before the wavelength conversion)) pass through. The phase of the light rays passing through the optical path OP1 (second pulse P2a (before wavelength conversion)) is 240 degrees different from the phase of light rays passing through the optical path OP3 (second pulse P2a (before the wavelength conversion)) pass through.

The rays of light that make up the optical path OP1 (second pulse P2a (before the wavelength conversion) with a wavelength W1 [nm]) experience a change in the optical path through the rhomboid prism 13a to go through the optical attenuator (ATT) 11a attenuated and the wavelength change section (PPLN) 14a to be fed. Furthermore, the wavelength change section (PPLN) 14a supplied light beams through the polarization reversing sections 144 from that at the predetermined distance D1 in the wavelength changing section 14a are arranged to perform a wavelength conversion in W2 [nm] to second pulses P2b (after the wavelength conversion) and are then passed through the filter (F) 172 subjected to removal of the pump beam and the idle beam to the dichroic mirror 164 to be fed.

The rays of light that make up the optical path OP2 (second pulse P2a (before the wavelength conversion) with a wavelength W1 [nm]) are passed through the optical attenuator (ATT) 11b attenuated and the wavelength change section (PPLN) 14b fed. Furthermore, the wavelength change section (PPLN) 14b supplied light beams through the polarization reversing sections 144 from that at the predetermined distance D2 in the wavelength changing section 14b are arranged to have a wavelength conversion in W3 [nm] as a second pulse P2b (after the wavelength conversion) to be experienced, and are and are then passed through the filter (F) 174 subjected to removal of the pump beam and the idle beam from the dichroic mirror 162 reflected and the dichroic mirror 164 to be fed.

The rays of light that make up the optical path OP3 (second pulse P2a (before the wavelength conversion) with a wavelength W1 [nm]) experience a change in the optical path through the rhomboid prism 13b to go through the optical attenuator (ATT) 11c attenuated and the wavelength change section (PPLN) 14c to be fed. Furthermore, the wavelength change section (PPLN) 14c supplied light beams through the polarization reversing sections 144 from that at the predetermined distance D3 in the wavelength changing section 14c are arranged to do a wavelength conversion in W4 [nm] to second pulses P2b (after the wavelength conversion) and are filtered through the filter (F) 176 subjected to removal of the pump beam and the idle beam to from the mirror 154 reflected and through the dichroic mirror 162 the dichroic mirror 164 to be fed.

Part of the second pulse P2b (after the wavelength conversion) by the wavelength changing sections 14a , 14b , 14c output and the wavelength W2 [nm], the wavelength W3 [nm] and the wavelength W4 [nm] are through the dichroic mirror 164 as a third pulse P3 multiplexed at a predetermined frequency (2 kHz).

The third pulse P3 go through the lens (L) 192 through and are attached to the optical fiber (MMF) 18th forwarded.

According to the fourth embodiment, the use of the two acousto-optic modulators (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) instead of the acousto-optic deflector 120 in the third embodiment, the irradiation with pulsed light of three wavelengths, as is the case in the third embodiment. It is noted that the (two) acousto-optic modulators are simpler and cheaper in the laser beam output device 1 than the acousto-optic deflector.

In the fourth embodiment as well, as in the third embodiment, there is only one LN crystal substrate 142 , with all polarization reversal sections 144 in the single LN crystal substrate 142 can be formed.

It is noted that the fourth embodiment may have the following variation in the operation of the optical path determination section (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) .

12 Fig. 13 is an enlarged view around the optical path determination portion (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) in the Laser beam output device 1 according to a variation of the fourth embodiment.

The first acousto-optic modulator (AOM) 12a is arranged so that he gets the first pulse P1 receives and one path of multiple optical paths OP1 , OP2 for each of the first pulses P1 intended for output. For example, the first acousto-optic modulator (AOM) 12a arranged to receive each of the first pulses P1 bends to output (optical path OP1 ) or forwards directly (optical path OP2 ). These are the same as in the fourth embodiment.

The second acousto-optic modulator (AOM) 12b is arranged here so that it receives the output of the first acousto-optical modulator (AOM) 12a receives and one path from one or more optical paths OP1 , OP2 , OP3 for each of the pulses of the output of the first acousto-optic modulator (AOM) 12a intended for output. In the variation of the fourth embodiment, the second acousto-optic modulator (AOM) is 12b arranged in such a way that it detects the directly transmitted pulses (optical path OP2 ) receives the first pulse for output and forwards it directly (optical path OP2 ) (“Does not bend”, which is different from the fourth embodiment), while using the diffracted pulse (optical path OP1 ) receives and diffracts the first pulses for output (optical path OP3 ) or forwards directly (optical path OP1 ) (“Bends”, which is different from the fourth embodiment).

It is noted that the shorter sides of the second acousto-optic modulator (AOM) 12b opposite the optical path OP1 are inclined counterclockwise by θB (Bragg angle).

Fifth embodiment

The laser beam output device 1 according to the fifth embodiment is different from the laser beam output device 1 according to the fourth embodiment mainly in that two acousto-optical modulators (a first acousto-optical modulator (AOM) 12a and a second acousto-optic modulator (AOM) 12b) as in the fourth embodiment can be used for irradiation with pulsed light of four wavelengths.

10 Fig. 10 shows a configuration of the laser beam output device 1 according to the fifth embodiment. 11 Fig. 13 is an enlarged view around the optical path determination portion (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) in the laser beam output device 1 according to the fifth embodiment.

The laser beam output device 1 According to the fifth embodiment comprises a pump laser (output section of a pulsed laser) 10, optical attenuators (ATT) 11a , 11b , 11c , 11d , a first acousto-optic modulator (AOM) 12a , a second acousto-optic modulator (AOM) 12b , rhomboid prisms 130 , 13d , 13e , 13f , Wavelength change sections (PPLN) 14a , 14b , 14c , 14d , a mirror 154 , dichroic mirrors (multiplexer) (DCM) 161 , 162 , 164 , Filter (F) 172 , 174 , 176 , 178 , an optical fiber (MMF) 18th , a timing circuit (section on timing) 19th and a lens (L) 192 . Components that are identical to those of the fourth embodiment are given the same reference numerals in the following to omit the description.

The pump laser (output section of a pulsed laser) 10, the optical attenuators (ATT) 11a , 11b , 11c , The Wavelength Changing Intervals (PPLN) 14a , 14b , 14c , the mirror 154 , the dichroic mirrors (multiplexer) (DCM) 162,164, the filters (F) 172 , 174 , 176 , the optical fiber (MMF) 18th , the timing circuit (timing section) 19th and the lens (L) 192 are identical to those in the fourth embodiment, and their description is omitted.

Note, however, that the mirror 154 is arranged so that it pulses the second pulse P2b (after wavelength conversion) that receives the optical path OP4 go through and take them to the dichroic mirror 161 reflected. The dichroic mirror (multiplexer) (DCM) 162 is arranged so that it pulses the second pulse P2b (after the wavelength conversion) that the optical path OP2 go through, and that of the dichroic mirror 161 reflected light beams and multiplexed to the dichroic mirror 164 reflected. The filter 176 is arranged to have the pump beam and the idle beam of the output of the wavelength changing section (PPLN) 14c for output to the dichroic mirror (multiplexer) 161 away.

The filter 178 is arranged to have the pump beam and the idle beam of the output of the wavelength changing section (PPLN) 14d for output to the mirror 154 away.

The section for determining the optical path has the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b on. Both the first acousto-optic modulator (AOM) 12a as well as the second acousto-optic modulator (AOM) 12b have a rectangular, planar shape.

The longer sides of the first acousto-optic modulator (AOM) 12a and the longer sides of the second acousto-optic modulator (AOM) 12b lie parallel to each other. It should be noted that the optical path OP4 by θB (Bragg angle) clockwise with respect to the shorter sides of the first acousto-optic modulator (AOM) 12a is inclined. One of the longer sides of the first acousto-optic modulator (AOM) 12a receives the first pulses P1 , while one of the longer sides of the second acousto-optic modulator (AOM) 12b the output of the first acousto-optic modulator 12a receives.

The first acousto-optic modulator (AOM) 12a is arranged so that he gets the first pulse P1 receives and one path of multiple optical paths OP1 , OP4 for each of the first pulses P1 intended for output. In the fifth embodiment, the first acousto-optic modulator (AOM) 12a arranged so that it gets every pulse of the first pulse P1 bends to output (optical path OP1 ) or forwards directly (optical path OP4 ).

The second acousto-optic modulator (AOM) 12b is arranged to receive the output of the first acousto-optic modulator 12a receives and one path from one or more optical paths OP1 , OP2 , OP3 , OP4 for each of the pulses of the output of the first acousto-optic modulator 12a intended for output. In the fifth embodiment, the second acousto-optic modulator (AOM) 12b arranged so that it emits each of the pulses from the output of the first acousto-optic modulator (AOM) 12a bends to output (optical path OP2 , OP3 ) or forwards directly (optical path OP1 , OP4 ). In detail the second acousto-optic modulator (AOM) 12b arranged in such a way that the directly transmitted pulses (optical path OP4 ) receives and diffracts the first pulses for output (optical path OP2 ) or forwards directly (optical path OP4 ), while he sees the diffracted pulses (optical path OP1 ) receives and diffracts the first pulses for output (optical path OP3 ) or forwards directly (optical path OP1 ).

At the point in time at which the section for determining the optical path (1 + 4N) -numbered (1st, 5th, 9th ...) pulses (where N represents an integer equal to or greater than o) of the first pulses P1 receives, an acoustic wave is sent to the first acousto-optic modulator (AOM) 12a provided during the second acousto-optic modulator (AOM) 12b no acoustic wave is supplied. The (1 + 4N) -numbered pulses of the first pulses P1 then traverse the optical path OP1 (please refer 11 ).

At the point in time at which the section for determining the optical path (2 + 4N) -numbered (2nd, 6th, 10 ...) pulses of the first pulses P1 receives the first acousto-optic modulator (AOM) 12a no acoustic wave fed during the second acousto-optic modulator (AOM) 12b an acoustic wave is supplied. The (2 + 4N) -numbered pulses of the first pulses P1 then traverse the optical path OP2 (please refer 11 ).

At the point in time at which the section for determining the optical path (3 + 4N) -numbered (3rd, 7th, 11th ...) pulses of the first pulses P1 receives, an acoustic wave is sent to the first acousto-optic modulator (AOM) 12a and an acoustic wave to the second acousto-optic modulator (AOM) 12b provided. The (3 + 4N) -numbered pulses of the first pulses P1 then traverse the optical path OP3 (please refer 11 ).

At the point in time at which the section for determining the optical path (4 + 4N) -numbered (4th, 8th, 12 ...) pulses of the first pulses P1 receives the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b no acoustic wave supplied. The (4 + 4N) -numbered pulses of the first pulses P1 then traverse the optical path OP4 (please refer 11 ).

As a result, the section for determining the optical path is on the multiple optical paths OP1 , OP2 , OP3 , OP4 second pulse each time P2a (before wavelength conversion) which have a frequency (1/2 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (four) of the plural optical paths and which are 90 degrees different Have phases.

The rhomboid prism 13c is arranged so that it pulses the second pulse P2a (before wavelength conversion) that receives the optical path OP1 and the optical path parallel to the optical path OP1 changed away. The rhomboid prism 13e is arranged so that it pulses the second pulse P2a (before wavelength conversion) received by the optical path OP2 pass through, and the optical path parallel to the optical path OP2 changed away. The rhomboid prism 13f is arranged so that it pulses the second pulse P2a (before wavelength conversion) that receives the optical path OP3 and the optical path parallel to the optical path OP3 changed away. The rhomboid prism 13d is arranged so that it pulses the second pulse P2a (before wavelength conversion) that receives the optical path OP4 and the optical path parallel to the optical path OP4 changed away.

The optical attenuator (ATT) 11d is arranged to pass through the optical path OP4 (Edition of the rhomboid prism 13d) attenuates the light rays passing through and changes them to the wavelength changing section (PPLN) 14d feeds.

The Wavelength Changing Section (PPLN) 14d is arranged so that it diverges from the rhomboid prism 13d Pulse of the second pulse P2a (Wavelength Wi [nm]) representing the optical path OP4 pass through, receives and converts them into second pulses P2b (Wavelength W5 [nm]). The arrangement of the wavelength changing section 14d corresponds to the predetermined distance D2 arranged polarization reversal sections 144 (where the predetermined distance D2 should be read as D4, which is different from D1, D2, and D3) and the LN crystal substrate 142 in which the polarization reversal sections 144 be formed as in 2 or 4th shown.

It is found that the LN crystal substrate which is the wavelength changing section 14a the LN crystal substrate which is the wavelength changing portion 14b the LN crystal substrate which is the wavelength changing portion 14c and the LN crystal substrate that is the wavelength changing portion 14d are not identical. That is, the LN crystal substrate that is the wavelength changing portion 14a the LN crystal substrate which is the wavelength changing portion 14b the LN crystal substrate which is the wavelength changing portion 14c and the LN crystal substrate that is the wavelength changing portion 14d each for the light rays (which make up the optical path OP1 , the optical path OP2 , the optical path OP3 and the optical path OP4 run through).

Next, an operation according to the fifth embodiment will be described.

The pump laser 10 first emits a laser beam with a predetermined wavelength W1 [nm] as the first pulse P1 with a predetermined frequency (e.g. 2 kHz). The first pulses P1 become the first acousto-optic modulator (AOM) 12a of the section for determining the optical path. The timing circuit 19th controls the timing of the output of the optical path determination section.

At the point in time at which the section for determining the optical path (1 + 4N) -numbered (1st, 5th, 9th ...) pulses (where N represents an integer equal to or greater than o) of the first pulses P1 receives, an acoustic wave is sent to the first acousto-optic modulator (AOM) 12a provided during the second acousto-optic modulator (AOM) 12b no acoustic wave is supplied. The (1 + 4N) -numbered pulses of the first pulses P1 then traverse the optical path OP1 (please refer 11 ). This causes the light rays that make up the optical path OP1 run through to second pulses P2a (before the wavelength conversion) at a frequency (1/2 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (four) of the plural optical paths.

At the point in time at which the section for determining the optical path (2 + 4N) -numbered (2nd, 6th, 10th ...) pulses of the first pulses P1 receives the first acousto-optic modulator (AOM) 12a no acoustic wave fed during the second acousto-optic modulator (AOM) 12b an acoustic wave is supplied. The (2 + 4N) -numbered pulses of the first pulses P1 then traverse the optical path OP2 (please refer 11 ). This causes the light rays that make up the optical path OP2 run through to second pulses P2a (before the wavelength conversion) at a frequency (1/2 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (four) of the plural optical paths.

At the point in time at which the section for determining the optical path (3 + 4N) -numbered (3rd, 7th, 11th ...) pulses of the first pulses P1 receives, an acoustic wave is sent to the first acousto-optic modulator (AOM) 12a and an acoustic wave to the second acousto-optic modulator (AOM) 12b provided. The (3 + 4N) -numbered pulses of the first pulses P1 then traverse the optical path OP3 (please refer 11 ). This causes the light rays that make up the optical path OP3 run through to second pulses P2a (before the wavelength conversion) at a frequency (1/2 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (four) of the plural optical paths.

At the point in time at which the section for determining the optical path (4 + 4N) -numbered (4th, 8th, 12th ...) pulses of the first pulses P1 receives no acoustic wave to the first acousto-optic modulator (AOM) 12a and no acoustic wave to the second acousto-optic modulator (AOM) 12b provided. The (4 + 4N) -numbered pulses of the first pulses P1 then traverse the optical path OP4 (please refer 11 ). This causes the light rays that make up the optical path OP4 run through to second pulses P2a (before the wavelength conversion) at a frequency (1/2 kHz) obtained by dividing the predetermined frequency (e.g. 2 kHz) by the number (four) of the plural optical paths.

In addition, the phase of the light rays that make the optical path differ OP1 (second pulse P2a (before the Wavelength conversion)) go through the phase of the light rays that make the optical path OP2 (second pulse P2a (before wavelength conversion)) traverse the phase of light rays that make the optical path OP3 (second pulse P2a (before the wavelength conversion)) and the phase of the light rays passing through the optical path OP4 (second pulse P2a (before wavelength conversion)) go through 90 degrees from each other.

The rays of light that make up the optical path OP1 (second pulse P2a (before the wavelength conversion) with a wavelength W1 [nm]) experience a change in the optical path through the rhomboid prism 130 to go through the optical attenuator (ATT) 11a attenuated and the wavelength change section (PPLN) 14a to be fed. Furthermore, the wavelength change section (PPLN) 14a supplied light beams through the polarization reversing sections 144 from that at the predetermined distance D1 in the wavelength changing section 14a are arranged to perform a wavelength conversion in W2 [nm] to second pulses P2b (after the wavelength conversion) and are then passed through the filter (F) 172 subjected to removal of the pump beam and the idle beam to the dichroic mirror 164 to be fed.

The rays of light that make up the optical path OP2 (second pulse P2a (before the wavelength conversion) with a wavelength W1 [nm]) experience a change in the optical path through the rhomboid prism 13e to go through the optical attenuator (ATT) 11b attenuated and the wavelength change section (PPLN) 14b to be fed. Furthermore, the wavelength change section (PPLN) 14b supplied light beams through the polarization reversing sections 144 from that at the predetermined distance D2 in the wavelength changing section 14b are arranged to do a wavelength conversion in W3 [nm] to second pulses P2b (after the wavelength conversion) and are then passed through the filter (F) 174 subjected to removal of the pump beam and the idle beam from the dichroic mirror 162 reflected and the dichroic mirror 164 to be fed.

The rays of light that make up the optical path OP3 (second pulse P2a (before the wavelength conversion) with a wavelength W1 [nm]) experience a change in the optical path through the rhomboid prism 13f to go through the optical attenuator (ATT) 11c attenuated and the wavelength change section (PPLN) 14c to be fed. Furthermore, the wavelength change section (PPLN) 14c supplied light beams through the polarization reversing sections 144 from that at the predetermined distance D3 in the wavelength changing section 14c are arranged to do a wavelength conversion in W4 [nm] to second pulses P2b (after the wavelength conversion) and are then passed through the filter (F) 176 subjected to removal of the pump beam and the idle beam to pass through the dichroic mirror 161 reflected and through the dichroic mirror 162 the dichroic mirror 164 to be fed.

The rays of light that make up the optical path OP4 (second pulse P2a (before the wavelength conversion) with a wavelength W1 [nm]) experience a change in the optical path through the rhomboid prism 13d to go through the optical attenuator (ATT) 11d attenuated and the wavelength change section (PPLN) 14d to be fed. Furthermore, the wavelength change section (PPLN) 14d supplied light beams through the polarization reversing sections 144 from that at the predetermined distance D4 in the wavelength changing section 14d are arranged to do a wavelength conversion in W5 [nm] to second pulses P2b (after the wavelength conversion) and are then passed through the filter (F) 178 subjected to removal of the pump beam and the idle beam to from the mirror 154 reflected and through the dichroic mirror 161 , 162 the dichroic mirror 164 to be fed.

Pulse of the second pulse P2b (after the wavelength conversion) by the wavelength changing sections 14a , 14b , 14c , 14d output and which is the wavelength W2 [nm], the wavelength W3 [nm], the wavelength W4 [nm] and the wavelength W5 [nm] are through the dichroic mirror 164 as a third pulse P3 multiplexed at a predetermined frequency (2 kHz).

The third pulse P3 go through the lens (L) 192 and are made of optical fiber (MMF) 18th fed.

According to the fifth embodiment, the use of the two acousto-optic modulators (the first acousto-optic modulator (AOM) 12a and the second acousto-optic modulator (AOM) 12b) as is the case in the fourth embodiment, the irradiation with pulsed light of four wavelengths, the number of which is greater than that in the fourth embodiment.

Also in the fifth embodiment, as in the third embodiment, there is only one LN crystal substrate 142 . All polarization reversal sections 144 can in the single LN crystal substrate 142 are formed.

Sixth embodiment

The sixth embodiment relates to an apparatus for measuring photoacoustic waves 100 with one of the laser beam output devices 1 according to the first, second, third, fourth and fifth embodiments (including their variations).

13 Fig. 13 is a functional block diagram showing a configuration of the photoacoustic wave measuring apparatus 100 according to the sixth embodiment of the present invention.

The device for measuring photoacoustic waves 100 according to the sixth embodiment is for measurement of an object to be measured 200 (including, but not limited to, a blood vessel of a newborn in the vicinity of a basal cell carcinoma to a depth of about 3 mm in the human body) and includes a laser beam output device 1 and a measuring section 4th .

The laser beam output device 1 is identical to one of the laser beam output devices 1 according to the first, second, third, fourth and fifth embodiments (including their variations). Note, however, that a laser beam PL emitted from the laser beam output device 1 is output, a result of the third pulse P3b (after filtering) is that of the optical fiber 18th in the first, second, third, fourth and fifth embodiments (including their variations). It should be noted that the laser beam output device 1 is arranged so that it corresponds to the measuring section 4th provides a trigger signal in synchronization with the timing at which the pulses of the laser beam PL are output.

The measurement section 4th is arranged so that the object to be measured 200 on the basis of a photoacoustic wave AW is measured, which at the object to be measured 200 is generated by the laser beam PL. It should be noted that the measuring section 4th is arranged to take measurements in synchronism with the trigger signal from the laser beam output device 1 performs.

Next, an operation according to the sixth embodiment will be described.

The laser beam output device 1 outputs a laser beam PL. The laser beam PL is similar to the third pulses P3b (after filtering).

The laser beam PL becomes the object to be measured 200 fed. Since the laser beam PL is thus the object to be measured 200 is supplied, a photoacoustic wave AW is generated.

The measurement section 4th measures the object to be measured 200 on the basis of the photoacoustic wave AW.

According to the sixth embodiment, the object to be measured can 200 be acted upon with the laser beam PL for photoacoustic measurements. In addition, the object to be measured 200 are irradiated with pulsed light of one wavelength and immediately thereafter with pulsed light of another wavelength, as in the first, second, third, fourth and fifth embodiments.

Seventh embodiment

The seventh embodiment relates to an apparatus for measuring photoacoustic waves 100 with one of the laser beam output devices 1 according to the first, second, third, fourth and fifth embodiments (including their variations) and an ultrasonic pulse output section 2 .

14th Fig. 13 is a functional block diagram showing a configuration of the photoacoustic wave measuring apparatus 100 according to the seventh embodiment of the present invention.

The device for measuring photoacoustic waves 100 according to the seventh embodiment is for measuring an object to be measured 200 (including but not limited to a blood vessel of a newborn in the vicinity of a basal cell carcinoma to a depth of about 3 mm in the human body) and comprises a laser beam output device 1 , an ultrasonic pulse output section 2 and a measuring section 4th .

The laser beam output device 1 is identical to one of the laser beam output devices 1 according to the first, second, third, fourth and fifth embodiments (including their variations). Note, however, that a laser beam PL emitted from the laser beam output device 1 is output, a result of the third pulse P3b (after filtering) is that of the optical fiber 18th in the first, second, third, fourth and fifth embodiments (including their variations). It should be noted that the laser beam output device 1 is arranged so that it corresponds to the measuring section 4th provides a trigger signal in synchronization with the timing at which the pulses of the laser beam PL are output.

The ultrasonic pulse output section 2 emits an ultrasonic pulse PU. It should be noted that the ultrasonic pulse output section 2 is arranged so that it corresponds to the measuring section 4th provides a trigger signal in synchronism with the time at which the pulses of the ultrasonic pulse PU are output.

The measuring section 4th is arranged so that the object to be measured 200 on the basis of a reflected wave US as a result of the reflection of the ultrasonic pulse PU on the object to be measured 200 and one on the object to be measured 200 photoacoustic wave AW generated by the laser beam PL is measured. It should be noted that the measuring section 4th is arranged to take measurements in synchronism with the trigger signals from the laser beam output device 1 and the ultrasonic pulse output section 2 performs.

Next, an operation according to the seventh embodiment will be described.

The laser beam output device 1 outputs a laser beam PL. The laser beam PL is similar to the third pulses P3b (after filtering). The ultrasonic pulse output section 2 emits an ultrasonic pulse PU.

The laser beam PL and the ultrasonic pulse PU become the object to be measured 200 fed. Since the laser beam PL is thus the object to be measured 200 is supplied, a photoacoustic wave AW is generated. The ultrasonic pulse PU becomes the object to be measured 200 fed and reflected by it. This reflection leads to a reflected wave US.

The measurement section 4th measures the object to be measured 200 on the basis of the reflected wave US and the photoacoustic wave AW.

According to the seventh embodiment, the object to be measured can 200 with the laser beam PL and the ultrasonic pulse PU for photo-ultrasonic measurements. In addition, the object to be measured 200 are irradiated with pulsed light of one wavelength and immediately thereafter with pulsed light of another wavelength, as in the first, second, third, fourth and fifth embodiments.

List of reference symbols

P1

first pulse

P2a

second pulse (before wavelength conversion)

P2b

second pulse (after wavelength conversion)

P3a

third pulse (before filtering)

P3b

third pulse (after filtering)

OP1, OP2, OP3, OP4

optical paths

1

Laser beam output device

10

Pump laser (output section of a pulsed laser)

11

optical attenuator (ATT)

12th

Acousto-optic modulator (section for determining the optical path) (AOM)

120

acousto-optic deflector (AOD) (section for determining the optical path)

13

rhomboid prisms

14, 14a, 14b

Wavelength Change Section (PPLN)

142

LN crystal substrate

144

Polarization reversal sections

15.154

mirror

16,162,164

dichroic mirror (multiplexer) (DCM)

17th

Filter (F)

18th

optical fiber (MMF)

2

Ultrasonic pulse output section

4th

Measuring section

100

Device for measuring photoacoustic waves

200

object to be measured

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• JP 2011107094 [0003]
• WO 2017/138619 [0003]
• JP 2016101393 [0003]

Claims (18)

Device for measuring photoacoustic waves, comprising: a laser beam output device that outputs a laser beam; and a measuring section that measures an object to be measured based on a photoacoustic wave generated on the object to be measured by the laser beam, wherein the laser beam output device comprises: a pulsed laser output section that outputs a laser beam having a predetermined wavelength as first pulses; an optical path determining section that receives the first pulses and determines one of a plurality of optical paths for each of the first pulses to be output; a wavelength changing section that receives light beams each passing through the plurality of optical paths and that changes the light beams to have their respective different wavelengths for output; and a multiplexer that multiplexes the outputs of the wavelength changing section. Device for measuring photoacoustic waves according to Claim 1 , further comprising an ultrasonic pulse output section that outputs an ultrasonic pulse, wherein the measuring section further measures a reflected wave as a result of the reflection of the ultrasonic pulse from the object to be measured. Device for measuring photoacoustic waves according to Claim 1 or 2 , wherein the first pulses have a predetermined frequency, and wherein the section for determining the optical path outputs second pulses on the plurality of optical paths, respectively, which have a frequency obtained by dividing the predetermined frequency by the number of the plurality of optical paths, and which each have their different phases. Device for measuring photoacoustic waves according to Claim 3 , wherein the multiplexer outputs third pulses at the predetermined frequency. Device for measuring photoacoustic waves according to one of Claims 1 to 4th wherein the output portion of a pulsed laser is a pump laser. Device for measuring photoacoustic waves according to one of Claims 1 to 4th wherein the section for determining the optical path is an acousto-optic modulator or an acousto-optic deflector. Device for measuring photoacoustic waves according to one of Claims 1 to 4th wherein the wavelength changing portion has polarization reversing portions arranged with a predetermined interval therebetween through which the passing light rays propagate, and the predetermined distance is different for each of the passing light rays. Device for measuring photoacoustic waves according to Claim 7 wherein the wavelength changing portion comprises a nonlinear optical crystal substrate with the polarization reversing portions formed therein, and wherein graphic centers of the polarization reversing portions are arranged on a straight line parallel to an X-axis of the nonlinear optical crystal substrate. Device for measuring photoacoustic waves according to Claim 7 , wherein the graphic centers of the polarization reversal sections are arranged on a straight line parallel to the direction of propagation of the light rays. Device for measuring photoacoustic waves according to Claim 7 wherein the wavelength changing portion comprises a nonlinear optical crystal substrate with all polarization reversing portions formed therein. Device for measuring photoacoustic waves according to Claim 7 wherein the wavelength changing portion comprises a nonlinear optical crystal substrate having the polarization reversing portions formed therein, and wherein the nonlinear optical crystal substrate is provided for each of the light rays passing therethrough which propagate therethrough. Device for measuring photoacoustic waves according to one of Claims 1 to 4th wherein the wavelength changing portion comprises a nonlinear optical crystal through which the light rays passing therethrough propagate. Device for measuring photoacoustic waves according to one of Claims 1 to 4th further comprising an optical fiber one end of which receives an output from the multiplexer for output at the other end thereof. Device for measuring photoacoustic waves according to one of Claims 1 to 4th further comprising a section for timing control which timers an output of the section for determining the optical path with an output of the first pulses. Device for measuring photoacoustic waves according to one of Claims 1 to 14th wherein the optical path determining section comprises: a first acousto-optical modulator receiving the first pulses and determining one of a plurality of optical paths for each pulse of the first pulses to be output; and a second acousto-optic modulator that receives an output from the first acousto-optic modulator and determines a path of one or more optical paths for output for each pulse of the output of the first acousto-optic modulator. Device for measuring photoacoustic waves according to Claim 15 , wherein the first acousto-optic modulator bends or directly forwards each pulse of the first pulses for output, and wherein the second acousto-optic modulator receives the directly passed pulses of the first pulses for output and diffracts or directly passes them on while it the diffracted pulses of the receives the first pulse for output and forwards it directly. Device for measuring photoacoustic waves according to Claim 15 , wherein the first acousto-optic modulator bends or directly forwards each pulse of the first pulses for output, and wherein the second acousto-optic modulator receives the diffracted pulses of the first pulses for output and diffracts or directly passes them on, while it bends the directly passed pulses of the receives the first pulse and forwards it directly for output. Device for measuring photoacoustic waves according to Claim 15 wherein the first acousto-optic modulator bends or directly forwards each pulse of the first pulses for output, and wherein the second acousto-optic modulator bends or directly forwards each pulse of the output of the first acousto-optic modulator for output.

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